Many types of microelectronic devices such as semiconductor devices and magnetic bubble domain devices are well known in the art. As smaller and smaller device structures are produced using fine line lithography, greater demands are made upon the fabrication techniques. This is particularly a problem with magnetic bubble domain devices in which thermal gradients may be produced at various localized areas where there is bubble switching replication or the like. The thermal gradients result in severe operating margin degradation because of thermal non-uniformities existing over the surface of large area magnetic bubble domain chips. Greater demands are placed upon the fabrication process. Particularly in the case of non-planar devices, in which various layers of materials are placed sequentially upon the original substrate. Such layers generally follow the contours of the preceding layers. Thus, in a multi-level device certain regions such as cross-over areas, corners, and the like are subject to various fabrication problems such as cracks, discontinuities, or other defects.
Moreover, device characterization by optical/visual techniques is difficult because of the lack of bubble domain contrast as bubble domain diameters decrease and as the layer of bubble domain material becomes thinner.
Non-planar bubble domain device operating margins suffer a degradation due to the fact that all the Permalloy elements cannot be located at the optimum spacing distance from the garnet. Further, higher drive field power is required to operate the non-planar device compared to planar devices. Therefore, bubble device component design compromises must be made to account for the non-planar nature of the topographical features.
All of the problems noted above affect yield and performance characteristics. However, no suitable solution has previously been proposed which can solve one or more of these shortcomings.